Inductor with a reinforced plastic form



Nov. 28, 19 7 s. A. ADAMS 3,355,688

INDUCTOR WITH A REINFORCED PLASTIC FORM Fil'ed Jan. 26, 1966 Fig./.

9/ 7 Sfan/ey A. Adams 42 44 1N VLNTOR. 46 r 46 BY wild WW United StatesPatent 3,355,688 INDUCTOR WITH A REINFORCED PLASTIC FORM Stanley A.Adams, South Haven, Mich., assignor to Adams Electronics, Inc, acorporation of Michigan Filed Jan. 26, 1966, Ser. No. 523,150 8 Claims.(Cl. 336-192) ABSTRACT OF THE DISCLOSURE A thermoplastic coil form fromwhich metalic terminal lugs project. Coil leads are soldered to theterminal lugs while assembled on the coil form. The lugs are secured toan end portion of the coil form and a heat resistant insert collar tofirmly hold the terminal lugs in place while the coil leads are beingsoldered.

This invention relates generally to new and useful improvements inelectrical components, and more particularly to a plastic coil formhaving a reinforced collar section.

Coil forms now in use are generally in the form of elongate hollowcylindrical members of paperboard, plastic or the like, having coilwindings thereon with the ends of the coil connected by soldering toterminal lugs. These terminal lugs are provided for convenientlyconnecting the coil form to various other electrical components. A majorproblem has been encountered, however, when soldering the coil ends tothe terminal lugs associated with plastic type coil forms. This probleminvolves the movement of the terminal lugs from their mounting on thecoil form during the soldering of the coil ends thereto inasmuch as theplastic coil forms have a tendency to melt due to the heat of soldering.Accordingly, when plastic coil forms are used, a holding device for thelugs and form has normally been required to prevent such lug movement.This invention provides means for allowing the use of plastic coil formswhile eliminating the necessity for such holding devices, as the problemof lug movement has been alleviated.

It is an object of the invention to provide a molded plastic coil formwith which there is no problem of lug movement when soldering the coilends to the terminal lugs.

It is another object of the present invention to provide a plastic coilform which is faster, more efiicient and easier to manufacture, andwhich additionally is less eX- pensive than previous similar coil forms.

It is a further object of the present invention to provide a plasticcoil form utilizing a reinforced collar for facilitating the attachmentof terminal lugs thereto, as well as preventing the movement of theterminal lugs during the attachment of the coil ends thereto.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is an elevational view of a coil form comprising a firstembodiment of the present invention;

FIGURE 2 is an elevational view of a coil form comprising a secondembodiment of the present invention;

FIGURE 3 is an enlarged partial vertical sectional view taken throughthe bottom end of the coil form illustrated in FIGURE 2; and

FIGURE 4 is an enlarged bottom plan view of the coil form illustrated inFIGURE 2.

Referring now more particularly to the drawings, and specifically toFIGURE 1, reference numeral generally denotes the coil form comprisingthe first embodiment of the present invention. The coil form 10 includesa coil form body 12 of elongate hollow tubular construction and which ispreferably of an insulating material such as nylon or other suitableplastic material. The coil form body 12 has mounted thereon in the usualor conventional fashion, a coil winding generally denoted by referencenumeral 14. Further, a plurality of lugs generally denoted by referencenumeral 16 are mounted at the bottom end of the coil form body 12, andthe ends 18 and 20 of the coil winding 14 are attached to first andsecond of the lugs 16 at the attach area generally denoted by thereference numeral 22. The coil ends 18 and 20 are preferably soldered tothe lugs 16 in the attach area 22. It will be appreciated from adescription of the second embodiment of the present invention infra, asillustrated in FIGURES 24, that the mounting of the lugs 16 on the coilform body 12 is generally similar for the two embodiments, the majordifference being in thelocation of the attach areas 22.

Referring now to FIGURES 2-4, it will be observed that a coil formgenerally denoted by reference numeral 24 is provided, the coil formbeing generally similar to the form 10 described above. The coil form 24includes a coil form body 26 which is identical to the body 12 describedabove, including enlarged end portion 28 having a thickened wall portion30. The internal diameter of the enlarged end portion 28 is slightlylarger than the internal diameter of the remainder or upper portion ofthe hollow tubular coil form body 26, and an annular shoulder 32 is thusdefined below the thickened wall 30, the shoulder 32 being provided fora purpose to be described more fully below.

A coil winding generally denoted by reference numeral 34 is mounted onthe coil form body 26 in the usual manner, the coil winding 34 havingthe ends 36 and 38 extending downwardly for mounting on first and secondof the terminal lugs generally denoted by reference numeral 40. Inasmuchas the coil form body 26 is of a plastic type material which has atendency to melt or flow upon the application of heat thereto, or isgenerally thermoplastic, it will be apparent that the heat appliedduring the soldering of the coil ends 36 and 38 to the terminal lugs 40will adversely affect the mounting of the terminal lugs on the coil formbody 26, causing the lugs to move. However, it should also be apparentthat the coil form body 26 will not melt or flow at the normal operatingtemperatures to which the body is subjected. Thus, in order to alleviateor prevent the foregoing problem, an insert generally denoted byreference numeral 42 is provided, the insert comprising a hollow tubularcollar 44 which is of approximately the same outer diameter as the innerdiameter of the enlarged end portion 28, having the same wall thicknessas the thickness of the shoulder 32. Thus, the collar 44 is adapted tofit snugly within the enlarged end portion 28 and against the shoulder32, the shoulder, of course, limiting the distance which the collar canbe mounted into the body 26. The collar 44 is preferably a phenolicimpregnated fibrous material such as paper or the like, which ispreferably thermo-setting so as not to be affected adversely by thesoldering heat.

Referring specifically now to FIGURE 3, it will be observed that theterminal lugs 40 include the bottom portion 46 which extends downwardlypast the end of the coil form body 26 and which, of course, allow thecoil form to be easily mounted on a printed circuit board or the like.The terminal lugs 40 further include a body portion 48 having struck outlegs 50' and 52 thereon for enabling the lugs 40 to be mounted on thecoil form body 26. Thus, it will be appreciated that during thefabrication of the coil form 24, the collar 44 is first inserted intothe enlarged end 28 and against the shoulder 32, and at this time thelugs 40 are inserted into the molded form and 7 3 a through the collar44, being clinched through aligned apertures in the body 26 asillustrated'best in FIGURES 3 and 4.

It will be observed in FIGURES 2-4 that the terminal lugs 40 eachinclude an outstanding upper end or head portion 54 to which the coilends 36 and 38 are normally mounted and soldered, as indicated by thenumeral 56, corresponding to the attach area 22 as described inreference to the embodiment of the invention illustrated in FIGURE 1.Thus, after the lugs 40 have been mounted as described above, the :coilends 36 and 38 will be soldered to the head 54 of first and second ofthe lugs, and although the application of heat during the solderingmakes it likely that the plastic coil form body 26 will begin to melt,the phenolic impregnated collar will not be affected by this heat andthus the terminal lugs 40 will be maintained in place and movementthereof will be eliminated. Of course, it will be appreciated that theembodiment of the invention illustrated in FIGURE 1 is quite similar inconstruction to that illustrated in FIG- URES 2-4, the lugs 16 nothaving the head portion 54 thereon to which the coil ends are attached,but the lugs otherwise being substantially identical. Thus, the lugholding devices formerly necessitated when soldering the coil ends tothe lugs are no longer needed to prevent lug movement due to the use ofthe collar inserts provided by the instant invention.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly, all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. In combination, a tubular body member of thermoplastic insulativematerial having a thermal-flow temperature lower than solderingtemperature, a plurality of lugs mounted on said body member, anelectrically conductive device mounted on said body member having leadssoldered to said lugs, and thermo-setting holding means mounted in saidbody member for preventing movement of said lugs relative to theelectrically eondu ctive device.

2. The combination of claim 1 wherein said body member includes anenlarged lower end and a shoulder provided in said lower end, saidthermo-setting holding means comprising a collar in said enlarged lowerend abutting the shoulder.

3. The combination of claim 2 wherein said electrically conductivedevice is a coil Winding and said tubular body member is an elongateplastic coil form having one end from which said lugs depend, said lugsincluding means thereon for clinching said lugs to said enlarged endportion of said body member, said clinching means extending through saidcellar as well as said body member, whereby movement of said lugs willbe prevented during application of soldering heat.

4. The combination of claim 1 wherein said thermosetting holding meanscomprises an insert element received internally within the tubulat body"member and fastening means extending through the body member forsecuring the lugs to the insert element.

5. The combination of claim 4 wherein said tubular body includes adiametrically enlarged end portion within which the insert element isreceived and from which the lugs project.

6. The combination of claim 5 wherein said fastening means includes legsstruck out from the lugs extending through aligned apertures in the bodymember and the insert element.

'7. The combination of claim 4 wherein said fastening means includeslegs struck out from the lugs extending through aligned apertures in thebody member and the insert element.

8. A coil form comprising, a generally cylindrical hollow body member ofa generally thermo-plastic material, a coil Winding mounted on said bodymember, a collar received in one end of said body member, said collarbeing of generally thermo-setting material, and a plurality of lugsmounted on said body member at said one end, said lugs including meansextending through generally aligned apertures in said body member andsaid collar whereby said collar will be retained m'thin said body memberand said lugs will be fixedly mounted on said body member ReferencesCited UNITED STATES PATENTS 2,751,5 3 /1956 Willyard r 336-192 x2,965,864 12/1960 Patka 336-192 x LEWIS H. MYERS, Primary Examiner.

E. GOLDBERG, Assistant Examiner.

1. IN COMBINATION, A TUBULAR BODY MEMBER OF THERMOPLASTIC INSULATIVEMATERIAL HAVING A THERMAL FLOW TEMPERATURE LOWER THAN SOLDERINGTEMPERATURE, A PLURALITY OF LUGS MOUNTED ON SAID BODY MEMBER, ANELECTRICALLY CONDUCTIVE DEVICE MOUNTED ON SAID BODY MEMBER HAVING LEADSSOLDERED TO SAID LUGS, AND THERMO-SETTING HOLDING MEANS MOUNTED IN SAIDBODY MEMBER FOR PREVENTING MOVEMENT OF SAID LUGS RELATIVE TO THEELECTRICALLY CONDUCTIVE DEVICE.